Timing mechanism



0. Z. BRtWER.

TIMING MECHANISM.

APPLICATION FILED No.4. Isla.

Patented Nov. 9, 1920e nvcnl'cz Oscar E E re wer kane, in the county of Spokane yand Stateof OSCAR Z. BREWER, OF SPOKNE, WASHINGTON.

TIMING Mnonnlvrslvr.V

specificaties of Letters Patent.

Application filed December 4, 1919. Serial No. 342,485.

To all 't0/wm may concer-a Y A Be it known that I, @scan Z. Bnnivnn, a

citizen of the United States, residing at Vbpol/Vashington, have invented certain nevv and useful Improvements in Timing Mechanisms, of Which'the following is a specication. Y

rlhe present invention relates to an iinproved timing mechanism for valve operating mechanism of internal combustion en"- gines of the four cycle type, by means of Which the action of the exhaust valve is al-` tered in relation to the inlet valve through gearing instrumental in changing the peripheral position of the exhaust valve shaft in its relation to the crank shaft or driving shaft.

The alteration in the relation of the driven or exhaust valve shaft to the driving or crank shaft of the engine is accomplished during the suspension ofthe operation of the ignition system of the internal combustion engine, but the fuel charge, although not exploded, is admitted to the cylinder of the engine, and as a result of retarding or advancing the action of the exhaust valve with relation to the inlet valve, two compression strokes, thel second and fourth of the cycle, are provided and through the medium of this compression a braking action is pro-1 duced by the action of the piston in the cylinder to retardl the movement of the engine and thus positively retard, as with a braking action, the motor vehicle to which the engine is appliedL for propulsion. y

The change in the peripheral relationship of the exhaust valve shaft and the crank shaft or driving shaft to alter the timing of the valves, is accomplished by manually operated mechanism located at the steering column of the motor vehicle and connected with the gearing which effects the change, as set forth in a contemporary application for pat" ent filed by me December ith, 1919, Serial No. 342,482, and which illustrates the broad principles of the present invention.

In the accompanying drawings I have illustrated a compact and facile mechanism embodying` the subject matter of the present invention, involving sprocket chain connections for operating the intake or fuel supply p valve shaft directly at all times from the crank shaft, and also for actuating the en haast valve shaft in a similar manner, with the addition of gearing whereby the relationship of the peripheral movement of the exhaust valve operating` shaft may he varied as to the rotation of the driving shaft,- all three shafts being revolved synchronously.

Figure 1 is a sectional view through the gear case attachedvto the crank or engine case of the engine, disclosing the inclosed gearing, the sectionbeing taken at `line l- `s1 of Fig. 2. f

Fig. 2 isa vievv of the mechanism at line 2-2 of Fig. 1. ,L Y The crank shaft 1 is actuated as usual from lthe engine and for ypurposes of the present invention is provided with a reduced extension or journal 2, upon which a small sprocket `Wheel 3 is keyed, and from this sprocket Wheel a sprocket chainfl passes over the sprocket Wheel 5, twice the sizeof the Wheel 3 and keyedto the shaftV 6 Which controls the action of the intake valvesV of the engine in usual manner, the Wheel 5 revolving at one-half the speed ofthe Wheel 3. y The cam shaft for controlling the action of the exhaust valve or valves of the engine in usual manner, is indicated by the nu:`

moral 7, the three shafts 1, 6, and being journaled as usual in the `engine casing 8, and a gear casing 9 is utilized to cover the gearing and attached to the engine casing.v

`Beyond its bearing, the. exhaust `valve operating shaft 7 is fashioned with a reduced extension or journal 10, projecting into the gear casing and alined with the shaft,iand at its extremity the'extension bears a lever arm 11 loosely journaled thereon by means of its hub l2 Which incases the extension, and the hub has an outwardly projecting boss 13, a retaining collar ll surrounding the boss and attached to the gear casing 9 to retain the hub on its journal against the tension of a spring 15 incased in the hub and bearing against the end of the journal 13.

The lever arm 11 is thus free to oscillate orl rock on its journal l0, and may be so rocked through the segmental rack 16 keyed on the Patented Nov. 9, 1920.

boss 13 and actuated through the oomplemen- Y tary rock arm 17 carried by the rock shaft 18 journaled at 19 in the this rock shaft 18 may be koperated from the steering column of the motor vehicle propelled by the engine, or, in other suitable manner, for the purpose described.

The lever arm 11 forms part of an oscillatable frame, the other members of the frame beingan' arm 19 loosely journalecl on the gear case 9, and

journal extension l() near the bearing for the shaft 7, and an arch bar 2O rigidly connecting these two arms, and in the free ends of these arms a stud shaft2l is loosely journaled, extending parallel with the enumeratedv shafts and revoluble about the axis of the exhaust valve shaft 7. Y

From the large Sprocket wheelr22 retained on the extension 2 by the cap 22f, a sprocket chain 23 passes over a sprocketV wheel 24: loosely journaled on the extension l() and attachedto Vrevolve as aV unit with a smaller gear wheel 25 which latter is continuously in mesh with a gear wheel 26 fixed on: the stud shaft 2l and the latter wheel may roll on the wheel 25. wheel 27, isalso fixed on ythe studvv shaft, which shaft it will beV 'remembered is free to revolve in its bearings'in the oscillatable arm or frame, and this wheel 'is continuously engaged with the gear wheel 28 fixed on the extension of the cam shaft?. Vrllhusit will be apparent that thecrank shaft l drives the exhaust valve shaft; through the medium of sprocket wheel 22, chain23, sprocketV wheel/24, gear 25, wheels 26-27 andffixed gear 28, the wheel 27 however, may be rolled about the wheel 2S withthe shaftfV as its axis of movement to change the relation of the peripheral movement of' the exhaust shaft to the crank shaft, as the oscillatable frame revolves about the shaft 7.

Assuming the crank shaftl-to turn in the direction of the arrow in Fig. l, and the gears and sprockets move as indicated, the normal action of the gearing in operating the valves will be accomplished. rlfhe gearing for changing the timing valve is operated, manually, from the steering column as described andy the Aboss 13 is moved to revolve the hub of arm 11 on the extensionlO, and for the sake of clearness,

assume that the crankshaft l remains stationary. The gear 25 will'be held stationary and gear 26 will be caused to roll `on it, turning gear' 27 through the same angle with respect to shaft 1. rlhe combined Vmovement A second, smaller, gearr of the exhaust of rolling gear 27 and the turning of the oscillatable .frame 171--19-20 will impart a i motion to gear 28 on the exhaust valve shaft 7, and in this manner the peripheral movement of the shaft 7 is changed with relation to that of the driving shaft or crankshaft l'. The change gear train is so proportioned that one turn of gearV 28 is effected by two turns of gear 22, thereforerone stroke of the engine piston (18()O turn of the crankshaft) will turn the gear 28 through an angle of 900, and since an advance of theV action of the exhaust valves of *160J or 180o with relation to the crank shaft produces the maximum braking effect, such action will be produced by the ratio of the diameters of the gears 25, 11 and 2T 28 as shown.

`What I claim is- 1. The Vcombination with the driving shaft and drivenshaft and driving connections comprising a sprocket wheel on each shaft and` a sprocket chain, the driven shaft being loose) -a gear hxed to said loose sprocket wheel on the' driven shaft and a fixedgear on said shaft, of v a frame oscillatable on the driven shaft and a looseshaft in said frame, and a pairef fixed gears on the'stud shaft engaging the (the wheel on Y fixed and loose Vgears on the driven shaft Y respectively. f

2. The combination with the driving shaft and driven shaft and driving connections therebetween, ,0f an oscillatable'frame liournaled on the driven shaft Vand comprising a lever arm with` a hub formed with an extended boss, a segmental rack fixed on the boss, a complementary rack and actuating v`rosonn Z. Basura. 

